British Pat. No. 1,358,062 discloses photosensitive compositions consisting of a nitrile rubber with an addition photopolymerizable tri or tetra-unsaturated ester derived from acrylic or methacrylic acid and an addition polymerization initiator activatable by actinic radiation. Plates made from these compositions are processable only via solvent wash out to produce soft flexible printing plates.
U.S Pat. No. 3,825,430 discloses a photosensitive composition containing a continuous phase of a light sensitive organic material and a discontinuous phase of a finely divided, elastomeric organic compound uniformly distributed through the continuous phase, i.e. a carboxyl containing, high molecular weight butadiene/acrylonitrile copolymer.
U.S. Pat. No. 4,177,074 discloses a photosensitive composition containing a high molecular weight butadiene/acrylonitrile copolymer which contains carboxyl groups and a low molecular weight butadiene polymer which may or may not contain carboxyl groups and an ethylenically unsaturated monomer, and a free-radical generating system. This composition has use as a flexographic printing plate but requires continuous replacement of the solvent during the washout (developing) stage.
U.S. Pat. No. 4,272,608 discloses photosensitive elastomeric compositions comprising a high molecular weight carboxylated butadiene/acrylonitrile copolymer in which at least 25% of the carboxyl groups are neutralized with a metal cation of Groups IIA or IIB of the periodic table and an ethylenically unsaturated monomer and a free radical generating system. This composition utility as a photosensitive flexographic printing plate but also has the disadvantage of requiring large quantities of wash solvent or solution during the washout stage.